English

Noun

Translations

Understory (or understorey) is the term for the
area of a forest which
grows in the shade of the emergent or forest canopy. Plants in the
understory consist of a mixture of seedlings and saplings of canopy
trees together with understory shrubs and herbs. Young canopy
trees often persist as suppressed juveniles for decades while they
wait for an opening in the forest overstory which will enable their
growth into the canopy. On the other hand, understory shrubs are
able to complete their life
cycle in the shade of the forest canopy. Also some small trees
such as dogwood and
holly rarely grow tall and
are generally understory trees.

Forest understories have lower light intensities.
The wavelengths of
light that are available are only a subset of those that are
available in full sunlight. Understory plants must therefore be
shade
tolerant—they must be able to photosynthesize
successfully with the limited amount of light that is available.
They are often able to use wavelengths not available to canopy
trees. In
temperate deciduous forests understory seedlings "leaf out"
before the canopy trees do. This is important because it allows the
understory plants a window in which to photosynthesize without the
canopy present. This brief period (usually 1–2 weeks) is often a
crucial period which allows the plant to maintain a net positive
carbon
balance over the course of the year.

Forest understories also have higher humidity
than exposed areas. The forest canopy reduces solar radiation, so
the ground does not heat up as rapidly. Consequently, the
understory dries out more slowly than does more exposed areas. The
greater humidity allows fungi and other decomposers to
flourish. This drives nutrient
cycling, and provides favorable microclimates for many
animals and plants.